Effects of plant extracts on T cell proliferation. Figure 5 shows the effects of plant extracts on human T cell proliferation. Each value represents the mean of six determinations. Values are the means ± SEM. (*) indicates significant difference compared with the only anti-CD3-stimulated cells (p < 0.01). NS = non-significant difference. Figure 5 insert shows the effects of different extracts at 20 μg/ml without stimulation by anti-CD3. Picra-EtOH: ethanolic fraction of Picralima nitida; Picra-But: butaniolic fraction of Picralima nitida; Nauclea-EtOH: ethanolic fraction of Nauclea latifolia; Nauclea-But: butanolic fraction of Nauclea latifolia; Oxy-EtOH: butanolic fraction of Oxytenanthera abyssinica; Picra-Aqos: aqueous fraction of Picralima nitida.